Our invention relates to apparatus for the transfer (recording and/or reproduction) of data to and/or from magnetic tape packaged in cassette form. More specifically, our invention deals with improvements in data transfer apparatus of the type described and claimed in U.S. Pat. No. 4,701,817 issued Oct. 20, 1987, to Uemura under the same title herewith and assigned to the assignee of our instant application. The data transfer apparatus of our invention is particularly well suited for the storage and retrieval of digitized data, although we do not wish our invention to be limited to this particular application.
In magnetic tape cassette apparatus in general, it is essential that the tape cassette on being loaded therein be precisely positioned with respect to the transducer or magnetic head for proper data transfer therewith. The usual construction of the tape cassette apparatus has been such, however, that the tape cassette on being inserted in the entrance slot of the apparatus is first moved to a preassigned data transfer position. Then the transducer is moved into contact with the tape of the positioned tape cassette preparatory to the commencement of data transfer. Since the tape cassette and the transducer are both independently movable in such apparatus, difficulties have been encountered in some instances in exactly positioning them with respect to each other.
A solution to this problem is found in the above cross-referenced U.S. Pat. No. 4,701,817. This patent makes the movement of the transducer unnecessary; only the tape cassette, on being loaded fully in the apparatus, is moved linearly to the data transfer position opposite the transducer. Then the pair of motor-driven spindles, forming parts of a tape transport, are moved into driving engagement with the hubs of the tape cassette being held in the data transfer position. The movements of the tape cassette to the data transfer position, and of the drive spindles into driving engagement with the cassette hubs, are both automatic, successively taking place upon loading of the tape cassette in the apparatus.
We have found some shortcomings in this prior art apparatus. One is the need for the provision of a complex and bulky tape transport shift mechanism for automatically moving the drive spindles into and out of driving engagement with the cassette hubs. Another shortcoming manifests itself in the use of what is known as the "cleaning cassette" for cleaning the gapped surface of the magnetic head and other required parts of the apparatus.
Such a cleaning cassette is described and claimed in Miyao et al. U.S. Pat. No. 4,748,526. Shaped and sized exactly like the magnetic tape cassette, the cleaning cassette is inserted in the entrance slot of the apparatus like the magnetic tape cassette. Thereupon, also like a the tape cassette, the cleaning cassette is automatically transported to the data transfer position, enabling the user to clean the head surface manually by inserting a cleaning stick in a guide passageway defined in the cleaning cassette. The cleaning cassette differs from the tape cassette in having no apertures for admitting the drive spindles. As the drive spindles are thus prevented from moving into the loaded cleaning cassette, so are the usual pair of tape guide pins which are disposed on both sides of the head. The operator can thus manipulate the cleaning stick without interference with the guide pins.
As has been stated, however, the apparatus is so constructed as to automatically actuate the drive spindles into driving engagement with the cassette hubs upon loading of the cassette in the apparatus. Therefore, upon insertion of the cleaning cassette, the drive spindles move into abutment against the bottom wall of the cleaning cassette under spring pressure. Such forced abutment of the drive spindles against the cleaning cassette gives rise to the danger of ruining the spindles or other parts associated therewith.